Sidney Blumenthal, a longtime ally of Hillary Clinton, testified all day Tuesday behind closed doors before a congressional panel probing the deadly 2012 attacks in Benghazi, Libya, but declared afterwards that he had "shed no light" on events there.

Two Libyan soldiers were killed and 15 were injured as heavy fighting erupted again between army forces and Islamist groups in the eastern city of Benghazi on Monday, medical staff and military officials said.

Eight people were killed, including seven children, when a rocket hit a residential building in the city of Benghazi in eastern Libya on Thursday, medics said, two days after a similar attack claimed by Islamic State militants.

When Libyan government forces and Islamist militants battled with artillery guns right in his district, Khalil al-Barassi knew it was time to pack up. He moved his family into an abandoned schoolhouse, where they live on aid from the Red Crescent, while the city around them falls to pieces.

The congressional panel investigating the 2012 attacks on a US mission in Benghazi called on former secretary of state Hillary Clinton on Thursday to testify at two public hearings, the first next month.

Militants claiming allegiance to Islamic State fought forces loyal to Libya`s two rival governments in the central city of Sirte and further east in Benghazi, state media and military officials said on Wednesday.

Eight civilians were killed in an air strike near Tripoli on Monday, the U.S. ambassador said, as Libya`s internationally recognised government pressed on with an assault to recapture the capital it abandoned to a rival faction last year.